1. Field of the Invention
This invention relates generally to workpiece support tools and fixtures, and more particularly to a clamping fixture for enabling the upright support of a door or window so that a carpenter may obtain work access to both sides of the workpiece for installing hardware, cutting mounting apertures, applying finishes, etc.
2. Description of Related Art
The following art defines the present state of this field:
Deutsch et al., U.S. Pat. No. 5,048,806 describes a collapsible frame used as a door hanging aid and provides for two articulating U shaped channel members respectively hinged at proximate ends, one to the other together with one of the arms, which moves into a vertical orthogonal position relative to the other arm, which rests on the floor. The vertical arms support two lateral inclined members which stabilize the unit in a vertical position. The vertical arm also has means to vary the effective width of the vertical channel of that arm so as to accommodate various thicknesses of doors and secure the door therein.
Ponce, U.S. Pat. No. 4,799,658 describes a clamp having movable and fixed ledges extending forwardly toward one another from posts on the clamp's halves. The movable ledge receives a door whose weight moves the ledge in a generally gravitationally downward direction to the post toward the post and to clamp the work piece there between. The fixed ledge is positioned in the path of movement of the door and the movable ledge to limit the movement and any excessive pressure which otherwise might be exerted on the door by the clamp halves. The clamp is mounted on a base which comprises angled piping to form a two-dimensional support for the clamp and the door. Insulated electrical wires extend through the piping. Sockets are secured at one or more ends of the piping, save for one, to provide electrical outlet connections for power tools. The insulated wire extends from the remaining piping end for connection to a conventional electrical outlet.
Willey, U.S. Pat. No. 4,695,067 describes a wheeled carrier for transporting elongated articles having a wheeled axle, a dynamic clamp for the article including spring biasing to return the clamp to a relaxed position when the article is removed therefrom, and a suspension extending between the clamp and the axle to absorb shocks transmitted from the wheels so that the clamping force on the article is substantially constant. A "T" handle will move the carrier when empty by picking up the entire carrier, due to its light weight.
Collins, U.S. Pat. No. 4,391,437 describes a clamp apparatus for holding a door or the like in a generally vertical plane while a workman is preparing the door for hanging within a frame. The apparatus includes a base having a pair of clamping members slidably mounted thereon and such members are connected to a foot operated lever which is operated to move the clamping members apart and a spring or other resilient member urges the clamping members toward each other.
Hutchinson, U.S. Pat. No. 4,168,827 describes a carpenter's door clamp device with two clamping segments hinged together so as to pivot apart for insertion and removal of the door. Fulcrum spacers are mounted on the bottom of one or both clamp segments to enable the clamp to operate by the weight of the door and also to permit quick opening and closing of the clamp by simply applying and removing foot pressure at the outer end of the clamp segment.
Smith et al., U.S. Pat. No. 1,715,722 describes a door supporting vise comprising a pair of hinged strips, a vise jaw fixed on one of the strips adjacent the hinge connection of the strips, a vise jaw mounted on the other strip adjacent the hinge connection of the strips and adjustable toward and away from the first jaw, and a leaf spring pivotally connected to one of the said to swing out laterally thereof, at times, or in line therewith, at times, to extend across the hinge connection and the other strip and normally exerting an upward force on the hinged ends of the strips whereby to hold the vise jaws apart to facilitate the introduction of the edge of a door between said jaws.
Marz et al., U.S. Pat. No. 848,837 describes a carpenter's floor vise comprising a combination of a base provided on its under side with legs, one at each end, whereby the same is supported with a clear space below it and between the legs. There being also spaced longitudinal, slots in the base between its legs, co-acting clamping jaws removably seated on the base whereby these jaws are positioned. The lugs of one jaw being hook-shaped to prevent displacement of this particular jaw, and a set-screw carried by the other jaw and occupying the slot below it whereby this jaw is adjustably held. The base upon which these jaws are mounted consists of an elongated piece of steel so that the weight of an object may act upon this base in a manner to actuate the jaws automatically for the purpose of gripping or releasing such object.
Butcher, U.S. Pat. No. 763,941 describes a floor vise composed of two frame members pivotally connected at their inner extremities and spring-supported whereby the pivoted parts of the members are normally supported above the outer extremities of the members and a jaw pivotally mounted upon each member and each jaw having an inclined slot and the member having a pin passing through the slot, each jaw being hollow, and a spring being coiled around the pin upon which each member is supported, and having its extremities engaging the jaw on the inside whereby the latter is supported in the uppermost position permitted by its slow.
Young, U.S. Pat. No. 689,376 describes a floor vise comprising two twin members hinged together at their inner or adjacent extremities, and a leaf-spring attached to one member and passing over the hinge to engagement with the opposite member, whereby the central part of the two members is normally spring-supported above the surface upon which their outer extremities or feet rest., a space being left between their inner extremities above the hinge, and cooperating clamping-blocks pivotally mounted on their inner extremities which are recessed to allow the blocks to swing and adjust themselves to the surface of the article to be held.
Smith, U.S. Pat. No. 611,340 describes a clamping device for supporting doors and comprising two base portions, and adjustable and removable clamping frame mounted upon each of the base portions and a connecting ling pivotally connecting the base portions for the purpose set forth.
The prior art teaches several clamping devices suitable for supporting a door or window in an upright attitude. However, the prior art does not teach that such a clamping support may be lightweight, portable and constructed with hinged leg construction so as to be highly compact when folded and yet provide significant clamping action when applied to a workpiece. The present invention fulfills these needs and provides further related advantages as described in the following summary.